Can you live off one acre of land?

I'm curious, is it possible to sustain oneself financially and physically solely from the resources found on just one acre of land? It seems like a challenging prospect, given the modern world's reliance on convenience and specialized economies of scale. Would someone have to become highly skilled in sustainable agriculture, self-sufficiency, and resource management to make such a lifestyle viable? What potential challenges might one face in trying to live off the land on just one acre?